A variety of systems for ventilating and aspirating secretions from the bronchial tree in the lungs of a patient have been proposed and are in use. One form of the currently available systems include a ventilator or respirator adapted to provide a flow of oxygenated air to a patient through a T-shaped tracheal tube adaptor which incorporates a port through which a separate single use suction catheter for the intermittent suctioning of mucous from the bronchial tree of a patient can be inserted. Although these systems have proven to be satisfactory for the ventilation of a patient, one major disadvantage in using these systems is that the aspiration of mucous from the patient requires the opening of the ventilation system and interruption of the ventilation process while a suction catheter is inserted into the patient's trachea. The act of interrupting the ventilation of a critically ill patient and then actually suctioning or aspirating air from their respiratory system for approximately 20 seconds may have a very deleterious effect on the patient. During the aspiration process, the alveolar gases in the lungs of the patient will also be removed in addition to the mucous. The loss of alveolar gases may result in hypoxia which may then cause further complications in the patient such as arrythmia or tachycardia. Because the hypoxia may continue in the patient for up to one hour, it is usually necessary to hyperoxygenate the patient before and after the aspiration to counter the oxygen deficit experienced during aspiration.
The aspiration of a patient's bronchial tree is usually required to be performed a number of times throughout a twenty-four hour period and therefore, numerous suction catheters are used in a twenty-four hour period with this type of catheter system. It is therefore desirable to provide a catheter system wherein the ventilation of the patient may be continued during aspiration and wherein the suction catheter is reusable.
In more recent times, the use of closed ventilation and suction catheter systems have been suggested to simultaneously ventilate and suction the bronchial tree or trachea of a patient. Some examples of such closed ventilation and suction catheter systems are disclosed in U.S. Pat. Nos. 3,991,762, 4,569,344, 4,638,539, 4,805,611, 4,834,726, 4,696,296 and 4,836,199. The use of these closed ventilation and suction catheter systems is a departure from the prior practice of opening the ventilation system and using a fresh suction catheter for each aspiration process. The above-identified closed ventilation and suction catheter systems provide a reusable suction catheter which is surrounded by a transparent envelope and which may be used without disconnecting the patient from the ventilator. One of the major advantages of this type of system is that the user may manipulate the catheter through the envelope without directly contacting the catheter either prior to or after insertion into the patient.
During the aspiration procedure, it is sometimes necessary to irrigate the upper bronchial tree or trachea of the patient to help break up thick accumulations of mucous in the patient. This is typically done by injecting a saline solution into the patient's airway through the T-shaped tracheal tube adaptor. The saline solution then drains down the patient's airway and is removed with the mucous through the suction catheter.
In a recently marketed closed ventilation and suction catheter system marketed by Concord/Portex of Keene, New Hampshire, USA, a dual lumen suction catheter is provided which includes an irrigation inlet port on the proximal end of the catheter. The irrigation inlet port includes a luer fitting thereon so that irrigation fluid may be supplied to the secondary lumen using either a syringe or a fluid filled capsule. The secondary lumen of this suction catheter opens approximately 1 centimeter from the distal end of the suction catheter. The proximal end of this catheter includes a single valve in communication with the primary lumen of the catheter and the secondary lumen is unobstructed between the proximal and distal ends of the catheter.